/*
 * @(#)$Id$
 * 
 * Copyright 2006-2008 Makoto YUI
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 * 
 * Contributors: Makoto YUI - initial implementation
 */
package jacky.lanlan.song.domain;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.Serializable;

/**
 * 
 * @author Makoto YUI (yuin405+xbird@gmail.com)
 */
public final class KeyValue<K extends Comparable<K> & Serializable, V extends Serializable> implements
		Comparable<KeyValue<K, V>>, Externalizable {
	private static final long serialVersionUID = -2404017844476627950L;

	private transient K key;

	private transient V value;

	public KeyValue() {
	}

	public KeyValue(K key) {
		if (key == null) { throw new IllegalArgumentException(); }
		this.key = key;
	}

	public KeyValue(K key, V value) {
		if (key == null) { throw new IllegalArgumentException(); }
		this.key = key;
		this.value = value;
	}

	public K getKey() {
		return key;
	}

	public void setKey(K key) {
		if (key == null) { throw new IllegalArgumentException(); }
		this.key = key;
	}

	public V getValue() {
		return value;
	}

	public void setValue(V value) {
		this.value = value;
	}

	public int compareTo(KeyValue<K, V> o) {
		K otherKey = o.getKey();
		return key.compareTo(otherKey);
	}

	@SuppressWarnings("unchecked")
	public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
		this.key = (K) in.readObject();
		this.value = (V) in.readObject();
	}

	public void writeExternal(ObjectOutput out) throws IOException {
		out.writeObject(key);
		out.writeObject(value);
	}

}
